How to debug sound problems

From FedoraProject

This page explains information that should be included when filing bugs related to sound. General sound problems - where the problem is observed across multiple applications - should usually be filed against the kernel, or PulseAudio (see below for instructions on determining whether the problem is PulseAudio-related). If the problem is observed only in a specific application, or only in applications which use a single sound library (such as SDL or OpenAL), the bug should be filed against that component.

Contents

Hardware information

It is always useful to include detailed information on your sound hardware when filing a sound-related bug. To produce this information, run this command:

alsa-info.sh --no-upload

It will generate a file containing detailed information about your sound hardware with the name /tmp/alsa-info.txt. Attach this file to your bug report.

Is it PulseAudio?

The easiest way to determine if a bug is related to PulseAudio or not is to temporarily disable PulseAudio. You can do this by removing the alsa-plugins-pulseaudio package:

yum remove alsa-plugins-pulseaudio

It may be necessary to log out and log back in after making this change. If the application you are testing with is configured to output directly to PulseAudio, you should re-configure it to output to ALSA. Now see if you can reproduce the problem. If you can still reproduce the problem, it is likely not a PulseAudio issue. If you cannot, it is likely a PulseAudio issue. If you determine that the issue seems to be related to PulseAudio, see the PulseAudio debugging page. To restore PulseAudio functionality after doing this test, simply re-install the alsa-plugins-pulseaudio package.

Mixer settings

If your problem is that you cannot hear any sound, or sound is at too low or too high a volume, you should try adjusting your mixer (volume control) settings. In KDE for all Fedora releases, and in GNOME for Fedora releases prior to Fedora 11, there is a volume control application accessible from a panel icon that can control all available volumes.

In GNOME on Fedora 11, you can find a mixer application that can control all volumes under System / Preferences / Advanced Volume Control in the menu system. If all else fails, you can use the command line alsamixer application: run it as alsamixer -c0, use the left and right arrow keys to scroll through all available channels, and the up and down arrow keys to raise or lower the volume of a channel. The M key toggles between muted and unmuted.

If you find that adjusting one of the non-standard volume controls (anything but Master or PCM) resolves your problem, please file a bug according to the instructions here.

Model parameter

If your problem is that you cannot hear any sound, or that some input or output jacks on your card are not working, the instructions in the Mixer settings section above did not help, and you have an Intel HDA-type sound adapter (almost all laptops, and most desktops, sold since 2007 do), you can try this. If these instructions seem too complex for you, don't worry: just file a bug with all the information you can provide.

In the /tmp/alsa-info.txt file you generated earlier, the Advanced information - PCI Vendor/Device/Subsystem ID's section should contain a Subsystem ID for your sound device, of the form 1412:1724 (two four-character ids separate by a colon). Do a web search for "(your-ID)" alsa - e.g. "1412:1724" alsa. This may turn up previous reports from other people with the same problem. Often you will find advice to set a particular model= parameter for your sound driver. To do this, create a file named /etc/modprobe.d/sound.conf, with the following contents:

options snd_hda_intel model=(recommended parameter)

For example:

options snd_hda_intel model=3stack

if the recommended model was '3stack'. After creating this file, reboot. If you find you can solve the problem this way, please include this information in your bug report.